Biology chapter 3 Flashcards
Amino Acid
An organic molecule containing a carboxyl
group and an amino group; serves as the monomer of proteins
Biological Macromolecule
important cellular components and perform a wide array of functions necessary for the survival and growth of living organisms. The four major classes of biological macromolecules are carbohydrates, lipids, proteins, and nucleic acids.
Carbohydrate
Biological molecules consisting of single-monomer sugars (monosaccharides),
two-monomer sugars (disaccharides), and polymers
(polysaccharides). Any of a large group of organic compounds occurring in foods and living tissues and including sugars, starch, and cellulose. They contain hydrogen and oxygen in the same ratio as water (2:1) and typically can be broken down to release energy in the animal body.
Cellulose
A structural polysaccharide of plant cell walls
composed of glucose monomers. Cellulose molecules are linked by
hydrogen bonds into cable-like fibrils.
Dehydration synthesis
the process of joining two molecules, or compounds, together following the removal of water.
Denaturation
A process in which a protein
unravels, losing its specific structure and hence function; can be
caused by changes in pH or salt concentration or by high temperature.
Denaturation also refers to the separation of the two strands of
the DNA double helix, caused by similar factors.
Deoxyribonucleic acid (DNA)
A double-
stranded helical nucleic acid molecule consisting of nucleotide
monomers with deoxyribose sugar and the nitrogenous bases adenine
(A), cytosine (C), guanine (G), and thymine (T). Capable of replicating,
DNA is an organism’s genetic material.
Enzyme
A macromolecule, usually a protein, that serves as a
biological catalyst, changing the rate of a chemical reaction without
being consumed by the reaction.
Glycogen
An extensively branched glucose storage polysaccharide
found in liver and muscle cells; the animal equivalent of
starch.
Hormone
In animals, a regulatory chemical that travels in the blood
from its production site, usually an endocrine gland, to other sites,
where target cells respond to the regulatory signal. (2) In plants,
a chemical that is produced in one part of the plant and travels to
another part, where it acts on target cells to change their functioning
Hydrolysis
A chemical reaction that breaks bonds
between two molecules by the addition of water; process by which
polymers are broken down and an essential part of digestion.
Lipid
An organic compound consisting mainly of carbon and hydrogen
atoms linked by nonpolar covalent bonds, making the compound
mostly hydrophobic. Lipids include fats, phospholipids, and steroids
and are insoluble in water.
Messenger RNA (mRNA)
The type of ribonucleic acid that encodes
genetic information from DNA and conveys it to ribosomes, where
the information is translated into amino acid sequences.
Monomer
The subunit that serves as a building block
of a polymer.
Monosaccharide
The simplest carbohydrate; a
simple sugar with a molecular formula that is generally some multiple
of CH2O. Monosaccharides are the monomers of disaccharides and
polysaccharides.
Nucleic acid
A polymer consisting of many nucleotide monomers;
serves as a blueprint for proteins and, through the actions of proteins,
for all cellular structures and activities. The two types of nucleic acids
are DNA and RNA.
Nucleotide
A building block of nucleic acids, consisting
of a five-carbon sugar covalently bonded to a nitrogenous base and
one or more phosphate groups.
Peptide bond
The covalent bond between two amino acid units in a
polypeptide, formed by a dehydration reaction.
Phospholipid
A lipid made up of glycerol joined to
two fatty acids and a phosphate group, giving the molecule two nonpolar
hydrophobic tails and a polar hydrophilic head. Phospholipids
form bilayers that function as biological membranes.
Polymer
A large molecule consisting of many identical
or similar monomers linked together by covalent bonds.
Polypeptide
A polymer (chain) of amino acids linked by peptide bonds.
Polysaccharide
A carbohydrate polymer of many
monosaccharides (sugars) linked by dehydration reactions.
Protein
A functional biological molecule consisting of one or more polypeptides
folded into a specific three-dimensional structure.
Purine
A nitrogenous base that has a large double ring structure. Makes up nucleic acids (e.g. DNA and RNA) and certain alkaloids (e.g. caffeine and theophylline)
Pyrimidine
A nitrogenous base that has a single-ring structure; one of the two general categories of nitrogenous bases found in DNA and RNA
Ribonucleic acid (RNA)
A type of nucleic acid consisting
of nucleotide monomers with a ribose sugar and the nitrogenous
bases adenine (A), cytosine (C), guanine (G), and uracil (U); usually
single-stranded; functions in protein synthesis, gene regulation,
and as the genome of some viruses.
Saturated fatty acid
A fatty acid in which all carbons in the hydrocarbon
tail are connected by single bonds and the maximum number of
hydrogen atoms are attached to the carbon skeleton. Saturated fats
and fatty acids solidify at room temperature.
Starch
A storage polysaccharide in plants; a polymer of glucose.
Transcription
The synthesis of RNA on a DNA template
Translation
The synthesis of a polypeptide using the genetic information
encoded in an mRNA molecule. There is a change of “language”
from nucleotides to amino acids.
Unsaturated fatty acid
A fatty acid that has one or more double
bonds between carbons in the hydrocarbon tail and thus lacks the
maximum number of hydrogen atoms. Unsaturated fats and fatty
acids do not solidify at room temperature.
